The Danish champions reached the group stage of Europe's top club competition last year, and finishing off the job against their Nordic neighbours would take them one step closer to a return.
Match preview
Within a minute of their 2023-24 European campaign getting under way, Copenhagen went 1-0 up in last Tuesday's first leg at Kopavogsvollur, as Jordan Larsson struck an early opener.
Rasmus Falk then doubled the Danish side's advantage before the half-time break, and a goalless second half leaves them firmly in the driving seat when Breidablik come to town for this week's second leg.
Copenhagen are ultimately aiming to repeat the feats of a successful 2022-23 season, when they won the domestic double and made a decent attempt at progressing from the Champions League group stage.
Unbeaten at home against Sevilla, Borussia Dortmund and eventual winners Manchester City, the Lions lost all three away games without scoring to finish bottom of the table. As a result, they have still made the knockout phase just once in the competition's current format, back in the 2010-11 campaign.
This year, they must yet overcome their Icelandic counterparts to set up a third-round tie with Sparta Prague, the winners of which would enter the all-important playoffs.
After kicking off the defence of their Danish Superliga title with a 2-1 win away to Lyngby - followed by Saturday's 3-2 success at Vejle, where Larsson scored the opener once again - Jacob Neestrup's men are certainly shaping up well for such a task.
By contrast with Wednesday's hosts, Breidablik are deep into their domestic season, sitting third in Iceland's Besta deild karla standings after a 1-1 draw against Stjarnan on Saturday.
Oskar Hrafn Thorvaldsson's side won the league by a 10-point margin last year, setting up an adventure into UEFA's premier club competition this summer.
After seeing off the champions of San Marino and Montenegro in a preliminary tournament hosted on home soil in Kopavogur, Breidablik then beat the Republic of Ireland's leading club Shamrock Rovers in the first qualifying round, but they now need an improbable comeback in Copenhagen to prolong their journey.
Defeat would mean demotion to the Europa League qualifiers, which at least provides a measure of consolation - and perhaps a more viable route into group-stage football for the very first time.
Copenhagen Champions League form:
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Copenhagen form (all competitions):
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Breidablik Champions League form:
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Breidablik form (all competitions):
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Team News
While Copenhagen have just signed Norway international Mohamed Elyounoussi on a four-year deal, the ex-Southampton forward is not eligible on Wednesday as he was not registered for the Champions League.
The hosts will also be without Viktor Claesson and David Khocholava due to injury, but Nicolai Boilesen has recently returned to training and could be handed a place on the bench.
Though Lukas Lerager and Valdemar Lund were both rested at the weekend, they could now return to Jacob Neestrup's starting XI in midfield and defence respectively, with in-form Swedish striker Jordan Larsson leading the line up front.
Breidablik, meanwhile, are still missing midfielder Patrik Johannesen due to a knee injury sustained in May.
Likely to adopt a flexible 4-2-3-1 formation, captain Hoskuldur Gunnlaugsson should start at right-back for the visitors, with Jason Dadi Svanthorsson or Faroese centre-forward Klaemint Olsen set to play the lone striker role.
Copenhagen possible starting lineup:
Grabara; Jelert, Vavro, Lund, Diks; Lerager, Clem, Falk; Bardghji, Larsson, Goncalves
Breidablik possible starting lineup:
Einarsson; Gunnlaugsson, Margeirsson, Muminovic, Ingvarsson; Sigurjonsson, Einarsson; Svanthorsson, Steindorsson, Yeoman; Olsen